Likely a hurricane at landfall, Harvey approaches a wary Texas

Posted by Eric Berger at 6:24 AM on August 24, 2017

Good morning. Tropical Storm Harvey has shown signs of better organization overnight, and now appears likely to become a Category 1 hurricane before landfall. However, given the warmth of the Gulf of Mexico and lowering wind shear levels, a stronger storm seems possible. As discussed Wednesday, models are increasingly focused on a landfall between Brownsville and Corpus Christi, and the National Hurricane Center has issued hurricane warnings for locations from Port Mansfield to Matagorda, Texas.

Tropical Storm Harvey forecast track. (National Hurricane Center)

This much of the forecast seems clear enough. Over the next two days, before Harvey makes landfall late on Friday or early Saturday, the storm will bring heavy rainfall, storm surge, and possible hurricane conditions to portions of the lower Texas coast. Through Saturday, some areas from South Padre Island through to Matagorda Bay, may receive a dozen inches of rain, or more. Barring a major change in forecast, locations further up the Texas coast, including Houston, will see seas rise 3 to 5 feet above normal levels, gusty winds, and perhaps 2 to 4 inches of rain through Saturday.

The key question for the upper Texas coast, including the Houston region, is what comes next.

As we’ve written about here for a couple of days, Harvey’s steering currents fall off once the storm moves inland, into southern Texas. For example, here’s how this morning’s ensemble GFS model predicts the location of Harvey’s center on Friday evening. Note the tight clustering of 50 different model runs—that means there is pretty high confidence in the solution as the storm nears the coast.

GFS ensemble model predictions for 6pm CT Friday. (Weather Bell)

However, when we fast forward to Tuesday morning, as depicted in the graphic below, and can see a broad spread in the model solutions for the center’s location. This uncertainty, also seen in the European model, reflects the challenging nature of the forecast for Texas and Houston early next week. Note that this forecast is for Harvey’s location three days after landfall, after the storm has moved inland, and the center has wobbled around. By Tuesday morning, about one quarter of the models have dragged the low into south Texas, the majority have brought the center back to the coast near Corpus Christi, or offshore. The remainder have brought the center up to Galveston and Houston.

Two scenarios

There are lots of possibilities for what will happen, obviously, but I think there are two distinct scenarios that will impact Houston’s weather. Since we are talking about weather events three to six days from now, there is already some uncertainty, but the erratic motion of Harvey, post-landfall, only adds to that.

Scenario One: Highway 59 or Gulf

This seems like the most likely scenario (75 percent), in which Harvey loops around the Rio Grande Valley and then gets pulled to the northeast, either moving back over the Gulf of Mexico (and toward Louisiana), or up the Highway 59 corridor through Houston. In either case the Houston metro region is going to get drenched. Under the Highway 59 track the entire region gets a lot of rain, probably 10 to 20 inches (with higher isolated amounts), and under the Gulf scenario the rains are much higher in the southern half of region, perhaps around Interstate 10 and points south. In this case, the heavy rains would probably not begin before late Saturday night or Sunday morning and persist, on and off, through Wednesday.

The official rain accumulation forecast from the National Hurricane Center reflects Highway 59/Gulf of Mexico scenario.

Scenario Two: Dying in the Rio

There is a lesser chance for this scenario (25 percent), but it seems plausible to me, and some of you have asked me about a “best case scenario.” This is a relatively good one for Houston, but a terrible one for South Texas, which picks up 20 inches of rain (plus or minus) and sees widespread flooding. In this scenario, some of the ensemble members show the center of the storm dragged inland long enough that it burns itself out before ever getting pulled northeast, toward Texas and Louisiana. Under this scenario, the Houston region would be largely “spared,” with perhaps 5 to 10 inches of rain spread over several days.

Key takeaways

It’s probable that a hurricane will make landfall along the southern Texas coast late Friday or early Saturday

This will not have immediate drastic effects for Houston, and while intermittent heavy storms and gusty winds are possible through Saturday, conditions for travel seem OK at this time.

By Sunday, running through about Wednesday, the greater Houston region will be at risk for very heavy rainfall and potentially widespread flooding, and coastal regions may be most at risk. If you are traveling later on Sunday or early next week, your flights may be delayed or canceled.

The forecast for next week remains highly speculative for Texas, but ranges from bad to very, very bad in terms of flooding potential.

Jeff

At this stage, (and I don’t want to be apocalyptic, but I do want to emphasize the seriousness) do you agree that this has a reasonably high potential to be the worst widespread flooding event (not more isolated to certain sections of the city) in Houston’s history?

Jessica

Jackie

Thank you very much for your thoughtful reporting. I’m a “charter” reader and have always enjoyed and appreciated your research and well-written information. Especially useful in a run-up situation like we have with Harvey. Great work!

Eric Berger

Sally

Thanks for the update! I am flying into Hobby on Sunday, arriving around 9 – 9 :30 am. I am concerned about the drive from Hobby to my house (near the heights). Based on the scenarios provided, do you think the streets will already be flooded? Thank you!

Elias

Jeremy

Eric: What are your thoughts on flight delays vs. cancellations flying into Hobby on Monday? I realize we can only speculate at this point, but as I need to get back Monday, I’m wondering if flying into a nearby airport and driving home to Houston would be a better option to avoid an outright cancellation. Thanks as always for your response and hype-free forecast.

Eric Berger

Robert LaPlant

Thank you so much, Eric. I appreciate these forecasts more than you can imagine! I need to take a quick trip to Wichita Falls and back on Friday, and you’ve given me sufficient confidence that I’ll be able to return before the worst has arrived. Thank you!

Dale Strickland

Joanne

We’re scheduled to fly back to IAH from Montrose CO on Monday (small regional jet) and thinking we should come home early. And if so, how much earlier. We want to be home for it , not away worrying as our area does get street flooding. Should we fly back Saturday? Or Friday ? Or even today ?

Donna

I am worried about my elderly mother who lives alone in the Southwest Houston area. Her house has flooded several times already & although she has talked about leaving (& been encouraged) she has yet to do so. What would you suggest in preparation for this storm? (Sandbags/water/etc) I’m already expecting her house to flood. She is not capable of lifting heavy objects. Worried about her right now, but I live in another state many hours away.

Eric Berger

Steve

You probably get tired of reading this, but this is the only place I count on for severe weather news without the drama. The local news has given no clarity whatsoever this morning – which is not at all surprising. Interviewing people gassing up their cars doesn’t really count as “news” to me.

Eric Berger

Kirsten

I tried to ask this last night, but can’t find it. So forgive me if it posted twice. I have family that just moved to Corpus Christi and is new to all this weather. I feel adequately prepared up here but am not sure what to advise them to do. Any suggestions based on what you’ve researched?

Stephen Mathew

Hello, thanks for the great information.
I am from Houston living out of state now, I have flights booked to visit this Saturday to Tuesday. If you were me and the Saturday morning flight were not cancelled would you still board?

Hux

Eric

Sorry if I’m double posting…
I live in the Clear Lake City area – and I’m primarily concerned with flooding. Not outright from Harvey’s landfall, but later in the weekend. Under scenario #1 – which you mentioned is more heavily favored at this time by the computer models – do you foresee any significant strengthening of Harvey either into a strong tropical storm or worse? That is if it does indeed return to sea, and trek eastward?

Eric Berger

Eric W

I currently have an international flight landing at IAH at 1:50pm on Saturday – sounds like it will be raining, but do what % chance do you think IAH will have significant delays or cancellations by then?

BC

KW

I’m an Okie with plans to travel, by car, to Houston Friday and returning back to OK Sunday. Would you advise us not to make the trip to Houston?
Great website, I wish more OK meteorologist took your no hype approach when it comes to OK’s server weather.

Eric Berger

Jim

The latest forecast track at NHC shows the center of the storm appearing to sit in place from Sunday morning into Monday, somewhere north of Corpus. Is this a likely scenario, or just an indicator of how uncertain the track is after landfall?

Eric Berger

maureen

What percentage of hurricanes approaching Houston turn clockwise vs counter clockwise? what influences the direction? Is there a significant difference in impact depending on the direction? which way did Allison turn?

Eleanor

I’m at the south corner of Westheimer and Kirby, how many inches do you think will fall in that exact spot? Also i have brunch plans on Sunday in Rice village, do you think it will be raining there at 11:50 AM on Sunday?

mary trevino

Ashli

My mom was planning to come into town tomorrow morning to help me with my kids during the storm since my husband will be working OT for most of it. We live in sienna plantation in Missouri City. If she comes do you think she would able to leave on sunday or should she plan to stay for a while?

Janie Heniford

We have tickets to Steven Tyler at Winstar Friday night. Had planned to head back to Houston Sunday morning. Looks like things may cooperate a bit to let us attend, but when do we need to head home Saturday afternoon or do you think Sunday AM travel will still be okay?

Eric Berger

Jay

I’m curious, and trying to understand why the 75% chance is that it comes thru Houston. The chart showing the various model predicts on Tuesday has a majority of models predicting still in the far south area. It seems like the more likely option is that it could stay well south of us based on that. Why isn’t “dying in the rio” a more likely outcome?

Nick

We have a vacation planned for September 20-25 in South Padre. How does the forecast currently look for SPI? No widespread destruction down that way? Just making sure we’ll still be good by then. Thanks for all the info.

Kimberly Renee Cima

Sorry for a question that applies to me alone, but I’m planning to travel to Fredericksburg Friday morning and return Sunday morning. Have a house booked for 17 people. We are trying to decide if we should cancel the trip. Freds will be fine, it’s the coming back we worry about. Do you think coming back Sunday morning is safe enough from what you know right now? Thanks for your updates, they’re great.

Eric Berger

Summer

I am astounded at all the travel advice that you are asked for! I don’t think you should feel obligated to play travel agent for all these folks. The short answer is that hurricanes are unpredictable, so the best advice is to be prepared for delays. That’s how it goes when Houston gets severe weather – flights are canceled, streets are flooded, and traffic is awful because people don’t stay where they are and think they can drive through high water.

Ray

Any idea how bad things will be in the Austin area? I have a flight for my SO coming into IAH Friday and going back out of IAH Sunday night. From what it sounds like the Sunday night flight is probably going to be delayed massively or cancelled… United isn’t letting me cancel and refund the trip right now because they say it’s too early to know how the storm will affect air travel through IAH (basically they’re telling her to come first and get stranded given what we expect about the storm). She needs to be back at work Monday morning so we don’t want to risk coming and getting stuck for and extra day or few but United did offer to reroute through another airport.

Joe

I’m supposed to fly into IAH from Minneapolis on Monday afternoon. I have a hotel on Crawford next to Minute Maid because I’m going to a bunch of Astros games all next week. Do you think I will be okay getting here or should I not even plan on coming now?

Paulette

Dear wonderful Eric who can foresee the future.
My hubby is in Greenwood Forest. A suburban is picking him up at 745am this Sunday to take him to IAH to catch an AA flight to Miami at 11am so we can go on our anniversary cruise. I’m flying to Miami from DCA.

Do you think he will make it to airport and AA flight will fly or will I be celebrating our 40th on the Ship ordering champagne for one only???

Karen Cobb

Hi, we have flights out of IAH Saturday morning (return Sunday evening) to Memphis….we live out on 290 off Barker Cypress. Should we cancel flights? Can we get to airport? Right now the flights are all showing “high alert” and allowing refunds….

Rene Jauregui

Hi Eric, I live in the Katy area and I am not from Texas. Meaning, I have no idea how to prepare for a hurricane of this magnitude (other than food and water, flashlights, batteries, medkits etc.,) Should I board up my windows as well?